Turbo?

[K5_DIESEL]

Does anybody know what the differences are between the GM-1, GM-3, GM-4, GM-5, GM-8? And Also what would be put one the stock 6.5L as a Turbo?

 

[Russell]

GM-3 has a mechanical waste gate, the rest of vacuum actuated. GM-8 is considered to be the best, spools the quickest and produces good boost.

I run a GM-3 on my engine, and it suits my needs perfectly well

 

[Wrench]

Primary difference is the bolt on elbow off the exhaust housing. Fab a custom flange with a 3" pipe that comes out straight and you'll be ahead of all of them.

 

[MaxPF]

They are all Borg Warner/IHI RHC6 turbos, but there are differences among them in configuration and turbine sizing. Most consider the GM8 the best, but it is actually very restrictive on the turbine side. IF you're sticking to a stock GM turbo the 3-8's are all adequate.